The present invention is generally related to sensor systems, and more specifically related to a system and method for maintaining correlated sonar and/or radar contacts.
In a typical active sonar/radar system, acoustic/electromagnetic signals are transmitted through a medium (e.g., water for sonar, air for radar) toward a target area and acoustic/electromagnetic returns (e.g., echoes) from the target area are received by receiving elements (e.g., sensors) and processed for display. In a passive system, no signals are transmitted. Thus, energy radiating from the target area is processed for display. Typically, detection and localization of a target of interest (also referred to as a contact) comprises determining the range and bearing to the target.
Many conventional systems use arrays of sensors and adaptively beamform the data received by the sensors to detect and/or localize targets of interest. However, traditional adaptive beamformers are known to cancel correlated contacts received by the system at approximately the same time. An example of such correlated contacts is multiple active echoes received by the system at the same time. In contrast, uncorrelated contacts are not cancelled.
Prior art attempts to maintain (also referred to as preserve) correlated contacts include spatial averaging techniques. However, traditional spatial averaging techniques suffer several disadvantages. Spatial averaging techniques tend to degrade array gain, thereby degrading detection and localization performance. Also, the matrices resulting from spatial averaging techniques are often cumbersome to manipulate and require extensive processing capability. Thus, a need exists for a system and process for preserving correlated contacts that overcome the herein-described disadvantages.
A system and method for processing received sensor array signals, which are indicative of correlated contacts, include forming a covariance matrix representation of elements associated with the received sensor array signals and adapting the covariance matrix representation of elements to obtain a Toeplitz matrix representation of elements. The Toeplitz matrix representation of elements is processed to obtain a response signal, which is indicative of a location of at least one of the correlated contacts.